ambassador chris stevens and three other americans. cnn pentagon correspondent barbara starr is working this story for us. barbara, what new are you learning? >> kate, let's explain to everybody what we're talking about here, when we say that in fact the u.s. intelligence community, the u.s. military is in the very preliminary stages of assembling target lists, possible militant personnel to go after inside libya responsible for that attack. it is what they do. the cia, the military commando units, they gathering intelligence. we know they have been doing that since the attack. they put it together, with all the information they have, satellite imagery, communication intercepts, what they know about a militant organization. some of these groups in eastern libya and they develop a potential target list. this is very preliminary work we are told, assembling that list so they will be ready if president obama were to ask for it. there's no decision to do it. it's not even ready, really. it's not fully cooked. still gathering intelligence,